Calculate the area of any room or space in square feet, meters, or acres.
Square footage measures the area of a two-dimensional space. For rectangles, multiply length by width. For triangles, multiply base by height and divide by two. For circles, multiply pi (3.14159) by the radius squared. Most rooms and properties are rectangular or can be broken into rectangular sections. This calculator handles common shapes individually and lets you combine multiple areas to get the total square footage of irregular floor plans.
When measuring a room, measure along the longest walls and include closets, alcoves, and bay windows that are part of the room's footprint. Measure in feet and inches, then convert inches to decimal feet (6 inches = 0.5 feet) before multiplying. For L-shaped rooms, divide the space into two rectangles, calculate each area, and add them together. This approach works for any irregular polygon by breaking it into simpler shapes.
Once you know your room dimensions, the Paint Calculator estimates gallons needed for walls and ceilings.
The Paver Calculator uses your area to estimate pavers and base materials needed.
Real estate square footage determines listing price, property taxes, and appraisal values. The ANSI Z765 standard (used by most appraisers) counts only finished, above-grade living space with a ceiling height of at least 7 feet. Finished basements, garages, porches, patios, and attics below 7 feet are excluded from the primary living area. This is why a finished basement adds value but does not appear in the official square footage number on most listings.
Price per square foot is the standard comparison metric in real estate. If a 2,000-square-foot home sells for $400,000, its price per square foot is $200. Comparing price per square foot across similar homes in the same neighborhood reveals whether a property is priced above or below the local market. Keep in mind that price per square foot varies significantly between urban and suburban locations, newer and older construction, and different levels of finish quality.
Flooring, painting, roofing, and landscaping projects all start with an accurate square footage measurement. For flooring, add 10 to 15% to your measured area to account for cuts, waste, and pattern matching. For paint, one gallon covers approximately 350 to 400 square feet on smooth surfaces. Multiply wall height by perimeter length to get wall area, subtract window and door openings, and divide by coverage per gallon to estimate how much paint you need. The Concrete Calculator handles volume estimates for poured projects.
Use a laser distance measurer for rooms over 10 feet in any dimension, as tape measures can sag or bow over long distances. Measure at floor level, not at waist height, because walls may not be perfectly vertical. For rooms with built-in bookshelves, fireplaces, or other protrusions, measure the full room and then subtract the footprint of each obstruction. Closets that are accessed from within the room are typically included in that room's square footage. Walk-in closets large enough to be their own space are sometimes measured separately.